Unusual oxidative Smiles reaction of quinine 1,10-phenanthro-2-yl-thioether with SO₂ extrusion

GRAPHICAL ABSTRACT

ABSTRACT

1-10-Phenanthrolin-2-ylsulfanyl quinine derivative was subjected to sulfoxidation. In comparison to phenylsulfanyl derivatives, the corresponding sulfoxide forms with difficulty. Application of sodium periodate system results in rather unexpected formation of an elimination product with migration of the phenanthroline residue and sulfur dioxide extrusion. This process most likely involves oxidation to sulfone followed by Smiles-type rearrangement. On the other hand, the sulfoxide is attainable with TEMPO/hypochlorite oxidation system.

KEYWORDS:

• Sulfoxidation
• sulfoxide
• Smiles rearrangement
• cinchona alkaloids
• phenanthroline

Funding

The authors are grateful to the National Science Centre, Poland for funding (Grant No. 2013/09/B/ST5/03410). DFT calculations have been carried out using resources provided by Wroclaw Centre for Networking and Supercomputing, grant no. 362.